Technical Field
The present disclosure generally relates to an organic light-emitting display device and, more particularly, to an organic light-emitting display device able to prevent light leakage.
Description of Related Art
Organic light-emitting display devices can be fabricated to be relatively light and thin, since organic electroluminescent (EL) devices or organic light-emitting diodes (OLEDs) able to emit light themselves are used therein and a separate light source is not required. In addition, organic light-emitting display devices are not only advantageous in terms of power consumption, since they are driven at low voltages, but also have desirable qualities, such as the ability to implement a range of colors, rapid response rates, wide viewing angles, and high contrast ratios. Thus, organic light-emitting display devices for next-generation displays have been actively researched.
Light generated by an organic light-emitting layer of an organic light-emitting display device is emitted from the organic light-emitting display device through several components of the organic light-emitting display device. However, a portion of light generated by the organic light-emitting layer may fail to exit the organic light-emitting display device and may be trapped therewithin, thereby causing a problem of low light extraction efficiency in the organic light-emitting display device.
Specifically, in the case of an organic light-emitting display device having a bottom emission structure, about 50% of light generated by the organic light-emitting layer may be trapped within the organic light-emitting display device through total internal reflection or light absorption by an anode electrode while about 30% of light generated by the organic light-emitting layer may be trapped within the organic light-emitting display device through total internal reflection or light absorption by a substrate. That is, about 80% of light generated by the organic light-emitting layer may be trapped within the organic light-emitting display device, and only about 20% of light may be emitted outwardly, leading to poor light extraction efficiency.
To improve the light extraction efficiency of organic light-emitting display devices, an approach of attaching a microlens array (MLA) to an overcoat layer of an organic light-emitting display device or an approach of forming microlenses on an overcoat layer of an organic light-emitting display device has been proposed.
When the MLA is disposed outside of a substrate of the organic light-emitting display device or the microlenses are formed on the overcoat layer, light generated by the organic light-emitting layer arrives at a polarizer through the substrate and is then reflected from the polarizer to be redirected toward the substrate. Here, a portion of light traveling toward the substrate may arrive at a microlens of an adjacent pixel on which a different color of light is generated, thereby causing light leakage, which is problematic.